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Field‐Effect transistors as transducers in biosensors for substrates of dehydrogenases
Author(s) -
Vering Thomas,
Schuhmann Wolfgang,
Schmidt HannsLudwig,
Mikolajick Thomas,
Falter Thomas,
Ryssel Heiner,
Janata Jiri
Publication year - 1994
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.1140061106
Subject(s) - isfet , biosensor , transistor , field effect transistor , redox , electrode , platinum , chemistry , dehydrogenase , transducer , threshold voltage , materials science , analytical chemistry (journal) , enzyme , optoelectronics , nanotechnology , voltage , inorganic chemistry , electrical engineering , chromatography , catalysis , biochemistry , engineering
A specially designed field‐effect transistor (FET) with a significantly enlarged gate area was applied in a classical urea enzyme FET (ENFET). The resulting high stability and sensitivity toward pH shifts make it predestinated for the measurement of H + produced in the equilibrium of NAD + ‐dependent enzymatic reactions, especially when the equilibrium is shifted by a subsequent reaction. As a model, the glucose dehydrogenase (GDH) reaction connected to an ion‐sensitive field‐effect transistor (ISFET) is demonstrated by which glucose could be determined in the range from 1 to 40 mM. A platinum electrode on the gate of the FET permits the measurement of reduction equivalents (NADH) by means of the recently, reported chronopotentiometrical methods. Thus, in principle, a way toward a redox ENFET is shown.